Specimens on approximately 100 individuals will be processed by two technicians under the contract. They will prepare karyotypes on peripheral blood specimens, bone marrow specimens, or skin fibroblast cultures supplied by the project officer. When required, specialized banding techniques will be utilized to further delineate chromosomal abnormalities. Complete reports of karyotype findings, including photographs where appropriate, will be sent to the project officer. At his request, stained or unstained slides will be supplied to collaborators for further analysis. Techniques for transporting specimens will be improved to maximize the quality of preparations.